Wednesday, July 28, 2010

In the London Review of Books, Peter Godfrey-Smith presents a very well-written and lucid criticism of Jerry Fodor and Massimo Piattelli-Palmarini's attack on evolutionary theory, What Darwin Got Wrong (2010). (For obvious reasons, I am going to refer to Fodor & Piattelli-Palmarini as F&P-P.) Their book has drawn lots of criticism from philosophers and scientists alike (e.g., here and here and here and here), so much so that yet another criticism might look like overkill; however, Godfrey-Smith's analysis is quite accessible and a pleasure to read. I am not going to review his whole review. I just want to point out one weakness I have found in it, and then I want to address F&P-P's response.

I have to question Godfrey-Smith on a point about counterfactuals. He notes that many philosophers discuss causality using counterfactuals, though he thinks this is optional. He says that, when we use counterfactuals to describe the causal relationships involved in natural selection, we are merely summarizing our prior analysis of the causal relationships. I think a lot of philosophers might take issue with that. According to counterfactual theories of causation, all causal claims can be explained, and not just summarized, with counterfactuals. While counterfactual theories of causation are debatable, I'm not so ready to reject them. I don't think we have to, either.

Godfrey-Smith makes the questionable point about counterfactuals in order to counter F&P-P's claim that "Selection cannot, as a matter of principle, be contingent upon (merely) counterfactual outcomes." The assumption is that, if our explanation of natural selection involves counterfactuals, then natural selection itself must involve counterfactuals--that the use of a counterfactual to explain natural selection implies a causal role for counterfactuals in the process of natural selection.

Unless I am missing something, this is just absurd. All causal claims are plausibly explainable in terms of counterfactuals; this does not mean that all (or any) events are counterfactual. I don't think the idea of a counterfactual event is coherent. It looks like a category error. Counterfactuals play a role in our explanation of causality, but not in the causes we are trying to explain. I do not think F&P-P have given us a reason to question the explanatory use of counterfactuals in evolutionary theory. For that reason, Godfrey-Smith's handling of the issue seems misguided. Other than that, I quite like his review (though I would prefer a more skeptical reading of Chomsky's attack on behaviorism).

As for the authors' response to the review, I again have to wonder if I am missing something, because it looks so ridiculous that it is hard to believe F&P-P are standing behind it. They write, "The theory of natural selection claims that the explanation as to why a particular kind of creature evolves a particular trait in a particular ecology, is that for that kind of creature in that situation, having the trait is a cause of fitness."

First of all, creatures don't evolve traits. Natural selection evolves traits through populations. The explanation for why some traits survive and become part of a population is that the traits make it more likely for individuals with them (within the population) to reproduce. We can say that "having the trait is a cause of [reproductive] fitness," though. That looks okay to me. (Some traits can be explained in other ways without creating any problems for Darwin; for example, they can be explained as piggy-backers, as Godfrey-Smith points out.)

F&P-P go on to say, "But then [natural selection] can’t also claim that ‘in the sense that matters’ ‘a trait was selected for’ means that it is a cause of reproductive success."

Why not? Why can't we say that the idea of selection fora trait just means that a trait was a cause of reproductive fitness/success relative to a competitive population?

Here's their answer: "If it did mean that, the theory of natural selection would reduce to a trait’s being a cause of reproductive success explains its being a cause of reproductive success, which explains nothing (and isn’t true)."

I don't see a coherent argument for this answer. According to natural selection, being a cause of reproductive success explains the presence of a trait in a population. That does not lead to the absurd conclusion F&P-P say it does, and I have no idea why anyone would think it does.

In the London Review of Books, Peter Godfrey-Smith presents a very well-written and lucid criticism of Jerry Fodor and Massimo Piattelli-Palmarini's attack on evolutionary theory, What Darwin Got Wrong (2010). (For obvious reasons, I am going to refer to Fodor & Piattelli-Palmarini as F&P-P.) Their book has drawn lots of criticism from philosophers and scientists alike (e.g., here and here and here and here), so much so that yet another criticism might look like overkill; however, Godfrey-Smith's analysis is quite accessible and a pleasure to read. I am not going to review his whole review. I just want to point out one weakness I have found in it, and then I want to address F&P-P's response.

I have to question Godfrey-Smith on a point about counterfactuals. He notes that many philosophers discuss causality using counterfactuals, though he thinks this is optional. He says that, when we use counterfactuals to describe the causal relationships involved in natural selection, we are merely summarizing our prior analysis of the causal relationships. I think a lot of philosophers might take issue with that. According to counterfactual theories of causation, all causal claims can be explained, and not just summarized, with counterfactuals. While counterfactual theories of causation are debatable, I'm not so ready to reject them. I don't think we have to, either.

Godfrey-Smith makes the questionable point about counterfactuals in order to counter F&P-P's claim that "Selection cannot, as a matter of principle, be contingent upon (merely) counterfactual outcomes." The assumption is that, if our explanation of natural selection involves counterfactuals, then natural selection itself must involve counterfactuals--that the use of a counterfactual to explain natural selection implies a causal role for counterfactuals in the process of natural selection.

Unless I am missing something, this is just absurd. All causal claims are plausibly explainable in terms of counterfactuals; this does not mean that all (or any) events are counterfactual. I don't think the idea of a counterfactual event is coherent. It looks like a category error. Counterfactuals play a role in our explanation of causality, but not in the causes we are trying to explain. I do not think F&P-P have given us a reason to question the explanatory use of counterfactuals in evolutionary theory. For that reason, Godfrey-Smith's handling of the issue seems misguided. Other than that, I quite like his review (though I would prefer a more skeptical reading of Chomsky's attack on behaviorism).

As for the authors' response to the review, I again have to wonder if I am missing something, because it looks so ridiculous that it is hard to believe F&P-P are standing behind it. They write, "The theory of natural selection claims that the explanation as to why a particular kind of creature evolves a particular trait in a particular ecology, is that for that kind of creature in that situation, having the trait is a cause of fitness."

First of all, creatures don't evolve traits. Natural selection evolves traits through populations. The explanation for why some traits survive and become part of a population is that the traits make it more likely for individuals with them (within the population) to reproduce. We can say that "having the trait is a cause of [reproductive] fitness," though. That looks okay to me. (Some traits can be explained in other ways without creating any problems for Darwin; for example, they can be explained as piggy-backers, as Godfrey-Smith points out.)

F&P-P go on to say, "But then [natural selection] can’t also claim that ‘in the sense that matters’ ‘a trait was selected for’ means that it is a cause of reproductive success."

Why not? Why can't we say that the idea of selection fora trait just means that a trait was a cause of reproductive fitness/success relative to a competitive population?

Here's their answer: "If it did mean that, the theory of natural selection would reduce to a trait’s being a cause of reproductive success explains its being a cause of reproductive success, which explains nothing (and isn’t true)."

I don't see a coherent argument for this answer. According to natural selection, being a cause of reproductive success explains the presence of a trait in a population. That does not lead to the absurd conclusion F&P-P say it does, and I have no idea why anyone would think it does.